Haha, what do you know. Compiled openMSX 0.13 yesterday on Ubuntu 16.10 (the repository still had 0.12 which gave problems with empty OSD menus) and tried this.

I would say expiriment successfull as it works with Softsynths but also with hardware like the Roland SC-88 module synthesizer using a Roland UM-01 USB-MIDI interface. So you can expand the manual with Hardsynth next to Softsynth